Larry Lebowitz, the COO of NYSE Euronext told the FT that even if he had kept the exchange open, the securities community wasn't ready to trade totally electronically. Their backup system, Arca, hasn't been implemented industry-wide.

Some firms even needed to rewrite code during the storm to get their trading programs up to snuff, which is dangerous.

Then there's what happened when major market maker, Knight Capital, had to shut down for the day because of a failed backup generator.

Bottom line: The last thing Wall Street needs is any perception of more problems with its electronic platforms. The SEC is already starting to look into market structure more, and that aside, after September 11th, Wall Street had emphasized being able to work remotely.